I. Field of the Invention
The present invention relates to the control of the operation of an internal combustion engine. It relates more particularly to the control of internal combustion engines intended to operate with various types of fuel.
II. Description of Related Art
Such operating control systems consist in managing the internal combustion engine by means of various sensors and actuating devices associated with a set of control parameters or software programs, stored in a processor mounted on the motor vehicle, called an “electronic control unit” (ECU). The ECU receives signals coming from all the sensors with which the vehicle is fitted, so as to enable the processor to identify the state of the engine in real time. From the physical values received by the processor contained in the ECU, it is able to control or regulate all the actuating devices of the engine for optimum operation.
To control a dual-fuel engine capable of operating with gasoline alone, with alcohol alone, or with a mixture of the two, one of the important signals which the ECU must take into account is the proportion of each of the two fuels contained in the main tank of the engine. In fact, the control parameters of the engine such as the ignition advance and the injection time must be adjusted according to this signal. It is therefore extremely important to know as accurately and as rapidly as possible which fuel or which mixture of fuels is present in the tank of the vehicle in order to adjust these various control parameters of the engine, to avoid damaging it and to minimize the emissions of pollutants.